Stevens was among the five schoolboys chosen as Wisden Cricketer of the Year in 1918 when he was attending University College School. In an inter-house match in May 1919 he made 466 not out and took 14 wickets, all in a single day. On his first-class debut a few days later he took 10 wickets for Middlesex against Hampshire at Lord’s. He was immediately selected to play for the Gentlemen, also at Lord’s.